Fixing piece for a windscreen wiper

ABSTRACT

A mounting part of a windshield wiper, having a receiving opening for a wiper shaft at one end, and forming a part of a fold-away hinge at the other end, and being formed from a flat sheet metal by deep-drawing, punching and bending and having a u-shaped cross-section profile and a spring mount. The spring mount is formed by deep-drawing from a sidewall of the u-shaped cross-section profile.

BACKGROUND INFORMATION

Known windshield wipers have a wiper arm, which is made up of a drivenmounting part and a hinge member that is connected to it by a hingedjoint and has a wiper rod. A wiper blade is pivoted at the free end ofthe wiper rod. The wiper blade is guided across the vehicle windshieldduring the swivel motion of the windshield wiper, an extension springprestressing the fold-away hinge, so that the wiper blade is pulledtoward the vehicle windshield.

The extension spring is accommodated in the u-shaped cross-sectionprofile of the articulated part and is suspended on the articulated partby one end using a cross-pin. By its other end, the extension spring isattached to a spring mount on the mounting part, via a c-shaped clip. Inknown mounting parts, this spring mount is either preformed or formed bya rivet pin. In one variant, for instance, mounting parts, designed assheet metal form parts, use a pin as spring mount. During manufacture,this is pressed into holes in the sidewalls of the u-shapedcross-section profile of the mounting part, and then riveted. Incontrast to a one-piece mounting part, this requires additionalproduction time for the installation and production of the additionalcomponents.

The spring mount is exposed to relatively high forces by the extensionspring. In the working position, or fold-away position, these forcesalso come to bear from different directions, with a 90° difference, forexample, resulting in a relative movement between the extension springor the c-shaped clip and their mountings. To achieve sufficiently highstrength, the mounting pin at the mounting part is usually made from adifferent material than the sheet metal bent component. However, whenjoining different materials, the danger of contact corrosion exists inthe interconnecting region.

In addition to a part of the fold-away hinge and a spring mount, themounting part also has a mounting region on the opposite end by whichthe wiper arm is rigidly, but detachably connected to a wiper shaft. Themounting region is designed as a shaft-hub-connection and is formed by areceiving opening having an inner cone, into which the free end of thewiper shaft, which is provided with an approriate outer cone, projects.The two parts are braced by a screw nut. There are also known variantsin which the conical interconnecting region is located between a collarof the screw nut and the receiving opening of the mounting part. Theform of the receiving opening is created in different ways. If themounting part is made of a die cast metal or plastic, the receivingopening is usually formed during the die-casting or injection molding,whereas it is produced in several drawing steps if sheet metal bentcomponents are involved.

SUMMARY OF THE INVENTION

In accordance with the present invention, the spring mount of a mountingpart designed as a sheet metal bent component is formed from a sidewallof the u-shaped cross-section profile by deep-drawing. Thus, the sheetmetal form part is designed as one piece and includes all the essentialfunctional elements, such as a receiving opening for a wiper shaft, apart of a fold-away hinge and a spring mount for an extension spring. Inorder to avoid subsequent assembly steps, as many functions as possibleare integrated in one component, which reduces production time and cost.Furthermore, there is no contact corrosion in a one-piece mounting part,since there are no critical connecting regions, at riveting pins, forinstance.

For better bracing or introduction of the spring forces in the sidewallof the u-profile, the deep-drawn spring mount has a conical shape thatwidens in the direction of the sidewall. As a result, the spring mounthas a sturdy design, resulting in minimal elastic deformation inresponse to forces, and, in this manner, minimizing, or entirelyeliminating, the effect on the application force of the wiper blade.

The spring mount has a round cross-section. It may also be oval, inwhich case it is expedient for the larger diameter to point in thedirection of the force of the extension spring when the wiper arm is inthe working position. The cross-section of the spring mount narrows fromthe sidewall to a necking, and then widens again from that point to thefree end. Furthermore, the necking contour is adapted to thecross-section contour of a c-shaped retaining clip, so that theextension spring is securely fastened and will not slide off themounting in response to vibrations. A lateral stop is required to anchorthe extension spring. This is created in a simple manner by compressingthe free end of the spring mount or, in a variant of the presentinvention, by punching and subsequent widening of the end region.

In order to reduce the friction between the spring mount and thec-shaped clip and thereby the wear resulting from the slight rotation ofthe c-clip during operation, the necking region is expediently providedwith a coating of a bearing material, such as plastic, or an additionalplastic ring. In this manner, the wiper arm can be folded back from thevehicle windshield more easily. The spring mount is preferablydeep-drawn from only one sidewall of the u-profile and projects into theu-shaped cross-section profile, up to its center region. In this manner,a clearance is created adjacent to the spring mount, in which, forinstance, the tube leading to the water supply of a windshield washersystem could be accommodated. Due to the deep-drawn spring mount, avisible insertion point is present on the side of the mounting part,located in a region that is either covered by the articulated part orpossibly by a protective cover. In this context, it is advantageous ifthe spring mount originates from a downward-pointing sidewall of themounting part, for instance pointing towards the vehicle hood, in orderto prevent dirt and water from accumulating in the hollow space of thespring mount which is open to the outside.

In accordance with the present invention, the spring mount is producedin several drawing steps. The material is first drawn in over a largearea, so that a uniform wall thickness across all regions is achieved.The conical region is then formed in several steps and a cylindricalregion at the closed end, as well as the end piece formed as a stop.Since the receiving opening for the wiper shaft is deep-drawn like thespring mount, both regions may be produced using one tool, in particularsince the production of both regions requires approximately the samenumber of drawing steps (approx. 5 to 7). While this may slightlyincrease the cost of the deep-drawing equipment, the machining time willnot be increased. In this manner, a cost-effective component is createdby producing the two strongly deformed areas of the mounting part with acomparatively low investment in tool manufacture.

The receiving opening and the spring mount are best produced in onephase in the still flat metal strip. The characteristic u-profile of themounting part is then produced by bending the sidewalls. After thisreforming process, the spring mount will be located on a sidewall andthe receiving opening for the shaft-hub-connection in the top wall. Ifrequired, the positional accuracy of the spring mount after bending maybe assured in a simple manner in an additional calibration step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective representation of a mounting part, in topview.

FIG. 2 one end of the mounting part having a spring mount, enlarged froma different perspective.

FIGS. 3–5 shows a part-sectional view of a flat metal part in the regionof the spring mount, during different production phases.

FIGS. 6–7 show variants of FIG. 5.

FIG. 8 shows a cross-section through a mounting part in the region ofthe spring mount, before bending of the sidewalls.

FIG. 9 shows a cross-section through a mounting part in the region ofthe spring mount, after bending of the sidewalls.

FIG. 10 shows a section through a receiving opening of the mountingpart.

DETAILED DESCRIPTION

A mounting part 10 of a windshield wiper is provided at one end with areceiving opening 12 or 46 for a wiper shaft 44 (FIG. 10) and forms part14 of a fold-away hinge at the other end (FIG. 1). Mounting part 10 alsohas a preformed spring mount 16 at this end, in which a c-shaped clip 18of an extension spring (not shown) engages. Spring mount 16 is formedfrom a sidewall 24 of the u-shaped cross-section profile 20 bydeep-drawing (FIGS. 2 and 9).

Relatively large tensile forces 64 and 66, respectively, are exerted onspring mount 16 from various directions, via c-shaped clip 18. Thecross-section of spring mount 16 has a correspondingly sturdy design, byhaving a round hollow section which has the largest cross-section in thearea transitioning to sidewall 24, and tapers to a necking 34. Necking34 forms the engagement area of c-shaped clip 18 and, therefore, has acontour 36 which is adapted to the cross-section contour of c-shapedclip 18. The cross-section of spring mount 16 increases again fromnecking 34 to the free end, so that a secure seat of c-shaped clip 18 isassured. This is of special importance, since c-shaped clip 18 executesa relative movement with respect to spring mount 16 during the fold-awayprocedure. In order to reduce the friction between c-shaped clip 18 andspring mount 16, the area of necking 34 is best coated with a bearingmaterial or surrounded by a ring made of plastic 70.

Spring mount 16 is deep-drawn during a phase when sheet 28 is stillflat. In this context, spherical indentation 56 is first formed bymaterial being drawn in over a large area (FIG. 3). A cylindrical part58 is then formed in several steps (FIG. 4). This is compressed inlateral direction 68 by an appropriate tool, thus creating necking 34(FIG. 5). In an exemplary embodiment of the present invention, necking34 is created by punching an opening 60 in the front-side base 38 ofcylindrical part 58, which is widened in a subsequent step (FIGS. 6 and7).

After forming spring mount 16, the parts of sidewalls 22 and 24 are bentin arrow direction 30 and 32, respectively, relative to the part of topwall 26, u-shaped cross-section profile 20 being formed from flat sheet28 (FIGS. 8 and 9). Spring mount 16 will then be located on sidewall 24and project with its free end into u-shaped cross-section profile 20.Necking 34 has a clearance 42 with respect to profile center 40 forlaterally fixating the extension spring. This clearance is producedafter bending in an additional calibration step.

Located on top wall 26 of u-shaped cross-section profile 20 is receivingopening 12. It has a conical shape, which projects into u-shapedcross-section profile 20 of mounting part 10 and tapers from top wall 26to a collar 62. FIG. 10 shows the mounting region of mounting part 10, areceiving opening 46 being shown as a variant. A wiper shaft 44 isprovided with cone 54 at its free end, which fits into conical receivingopening 46. Mounting part 10 and wiper shaft 44 are fixedly, butdetachably interconnected, by screwing screw nut 50 onto a threaded stud48. For additional safeguarding of the firm connection, cone 54 isprovided with knurling, and a disk 52 is positioned between mountingpart 10 and screw nut 50. Receiving opening 12 or 46 is best produced bydeep-drawing. In accordance with the present invention, spring mount 16is also deep-drawn on mounting part 10, and both deep-drawn regions areproduced on flat sheet 28 in one phase.

1. A mounting part of a windshield wiper, the mounting part having afirst end and a second end, the mounting part being produced from a flatsheet metal by deep-drawing, punching and bending, the mounting parthaving a u-shaped cross-section profile, the mounting part comprising: areceiving opening for a wiper shaft at the first end; a part of a hingedjoint at the second end; and a spring mount formed by a deep-drawingfrom a sidewall of the u-shaped cross-section profile, wherein across-section of the spring mount tapers from the sidewall to a necking,and increases in cross-section from the necking to a free end.
 2. Themounting part according to claim 1, wherein a contour of the necking isadapted to a cross-section contour of a c-shaped clip.
 3. The mountingpart according to claim 1, wherein a front-side base of the spring mounthas an opening at the free end of the spring mount.
 4. The mounting partaccording to claim 1, wherein the receiving opening widens conicallytowards a top wall of the u-shaped cross-section profile and, at an endpointing to a center of the receiving opening into the mounting part,has a collar.
 5. The mounting part according to claim 1, wherein thereceiving opening tapers conically towards a top wall.
 6. The mountingpart according to claim 1, wherein the spring mount is one of (a) coatedwith a bearing material and (b) surrounded by a ring of plastic in aregion where a c-shaped clip engages.
 7. A method of producing amounting part as recited in claim 1, comprising: forming a spring mountinitially in a flat sheet metal by deep drawing; and subsequentlybending parts of sidewalls of the mounting part relative to a part of atop wall of the mounting part.
 8. The method according to claim 7,further comprising producing a necking of the spring mount bycompression of the spring mount in a longitudinal direction.
 9. Themethod according to claim 7, wherein a necking is produced by wideningan opening in a base of the spring mount.
 10. The method according toclaim 7, further comprising producing a receiving opening simultaneouslywith the spring mount, prior to bending the sidewalls.